Fire control computer



Oct. 13, 1936. 2,057,261

S. G. MYERS ET AL FIRE CONTROL COMPUTER Filed Feb. 11, 1933 12Sheets-Sheet 1 INVENTORS: @wmnzm @NYERS 3' 5 791117 621m 1 G/MFHE.

Oct. 13, 1936. s. G. MYERS ET AL 2,057,261

FIRE CONTROL COMPUTER Filed Feb. 11, 1933 12 Sheets-Sheet 2 INVENTOR5(SH/ERF/ELD Ci/VYERS 5m 14/. GHHFEE.

Oct. 13, 1936. s. G. MYERS ET AL 2,057,261

FIRE CONTROL COMPUTER Filed Feb. 11, 1935 12 Sheets-Sheet 3 INVENTOHSOct. 13, 1936. s. G. MYERS ET AL 2,057,261

FIRE CONTROL COMPUTER l2 Sheets-Sheet 4 Filed Feb. ll, 1955 -/65 IG6LC/79 /69 L ummumhmmw M r MW /7/- we izm $2 59m MGHHFEE.

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Oct. 13,1936. s. G. MYERS ET AL 2,057,261

FIRE CONTROL COMPUTER Filed Feb. 11, 1933 12 Sheets-Sheet s i i 5 gas tx:Li'

5 50 l 5 l I i i 'NVENTORS: 42 44 (SH/EIPHELD G. MYERS fl/RL MU/MFEE.1,2"

1936. s. G. MYERS ET AL FIRE CONTROL COMPUTER Filed Feb. 11, 1953 12Sheets-Sheet 6 aa-i M P W 62m W. CHM-"5.

B d WAHOQ Oct. 13, 1936. s. G. MYERS ET AL 2,057,261

FIRE CONTROL COMPUTER Filed Feb. 11, 1953 12 Sheets-Sheet 7 \5 G [Eb I go JIL - INVENFORS:

l Slam/W10 G. NYERsQ 22m W, CHHFEE.

1' i ATTORNEY Oct. 13, 1936. s, MYERS ET AL 2,057,261

FIRE CONTROL COMPUTER Filed Feb. 11, 1933 12 Sheets-Sheet 9 INVE N TO RS2 CSfl/ERFIELD a/vymfi 5151 W. GHA FEE.

YERS ET T L C0 tats-sheet L C EE Oct. 13, 1936. 5 MYERS ET AL 2,057,261

FIRE CONTROL COMPUTER Filed Feb. 11, 1933 12 Sheets-Sheet 11 7, l0 7 V l[64/ 5 ATTORNEY.

Oct. 13, 1936. s. G. MYERS ET AL 2,057,261

FIRE CONTROL COMPUTER Filed Feb. 11, 1933 12 Sheets-Sheet 12 as as 252m2 ZI I' ORNEY Patented Oct. 13, 1936 UNITED STATES FIRE CONTROLCOMPUTER Shierfield G. Myers, Freeport, and Earl W. Chafee, Brooklyn, N.Y., assignors to Sperry Gyroscope Company, Inc., Brooklyn, N. Y., acorporation of New York Application February 11, 1933, Serial No.656,381

13 Claims.

This invention relates ,to a universal computing device for the controlof long range gun fire, especially where a pair or pairs of spaced basestations may be employed for sighting on the target. Our device hence isespecially adapted for seacoast batteries. One object of the inventionis to make such a device as complete as possible sothat the graphicallayout of the problem by hand on the plotting board is eliminated.

Another object is to so construct such a device that it may be used withdifi'erent pairs of sighting devices connected with the same batterysimply by changing a few settings on the machine. A third object of theinvention is to improve the reliability of such devices so that if onemethod of receiving data or one base station is crippled, another methodor pair of base stations can be substituted in the machine withoutdelay.

Referring to the drawings showing one form our invention may assume.

Figs. 1A, 1B, 1C and 1D represent successive parts of a completediagrammatic layout of our invention, the parts being separated alongthe marginal dot and dash lines.

Fig. 2 is a bottom plan view of one of the angle resolving mechanisms bywhich a sine or cosine function of one of the angles used is combinedwith another known factor to derive an unknown factor.

Fig. 3 is a sectional detail of the same.

Fig. 4 is another sectional detail taken approximately on line 4--4 ofFig. 2.

Fig. 5 is a bottom plan view of one of the mechanisms used to computethe future position of the target along one coordinate at the time theshell strikes.

Fig. 6 is a side view of a complete computer as it appears to anobserver.

Fig. 7 is a side view from the opposite side of the instrument.

Fig. 8 is an end view of the same.

Fig. 9 shows one of the lift cam mechanisms for introducing proper timeof flight for range.

Fig. 10 is a diagram showing the mathematical principles involved andapplicants solution of the problem.

Fig. 10A is a simplified diagram showing the derivation of the equationsused.

Fig, 11 shows one of the indicators that appears on the other end of thebox, namely, the indicator showing the true course and speed of thetarget.

Fig. 12 is a detail thereof showing the holding mechanism for one crosshair.

Fig. 13 is another detail of the top plate which has been removed inFig. 11.

Fig. 14 is a plan view, partly in section, of a series of cam followersused on the time of flight cams (see Fig. 9).

Fig. 15 is a detail of a portion of this mechanism combined with asimplified wiring diagram.

Fig. 16 is a vertical section through the contact mechanism connectedtherewith.

Fig. 1'7 is a diagrammatic view of the operating mechanism for one ofthe angle indicators.

Fig. 18 is a wiring diagram of the follow-up mechanism for parts of thecomputing mechanism.

Fig. 19 is a. diagram used in explaining the same.

Fig. 20 is a diagram showing a modified form of the invention.

Fig. 21 is a top plan view of a portion of the plotting device.

The mathematical principles around which our computer is designed arebased on what may be termed a circle diagram (see Fig. 10) in which acircle C is described to include both base stations B1-Bz and the targetT... It is obvious that 20 a circle may always be drawn through anythree given points. The distance between the base stations line B2-B1is, of course, known as is also the position of this line in azimuth,that is, the angle it makes with reference to the north-south line 0, i.e.

The location of the battery DP is also known with respect to the basestations, this location being preferably defined by X and Y componentsfrom one or the other of the base stations, say B2, the respectivecomponents being marked X11? and Yup. The sighting telescopes in thebase stations determine the sighting angles to the target, i. e. 1 and2. The triangle (B2 To Bl) thus formed within the circle of radius (r)contains an angle (m) at the target (To) which is used in thecomputations. A second angle (454) at the center of the circle, formedby a line drawn through the center of the circle parallel to the baseline and a. radius (r) to the target (To), is also used in thecomputations.

The radius (r) of the circle is combined trigonometrically with the sum(4) or difference (3) of the observed base end station angles (2 and mlto continuously obtain and indicate the linear coordinates of thepresent position of the target. In some cases the range may be knownfrom one or the other base stations. From this known data or a partthereof, the problem is to .obtain automatically, without plottingboards or numerical calculations, all the necessary data to direct thefire at the target.

In Fig. 10 the following equations may be easily R R sin q5= R R3231 9.R R (us g 2) R R, cos A 14. 12, 12,, sin A AP=AB2B1+APB Using thefollowing nomenclature:

B2 and B1 Base end stations R3731 Base line length 432 and rbi Base endstation azimuths to target R and R Base end station ranges to target Toand Tp Present and predicted target positions R and R Present targetposition coordinates S Target speed t Time of flight to predictedposition Sx and Sy Target component speeds St Distance target moves oncourse in time t Sxt and S t Target coordinate setforward distances DPDirecting point or battery X15? and YDP Directing point coordinates Rand R Target predicted pos. coordinates from DP Rp and A1) (ApB) Targetpredicted range and azimuth from DP A3213l True azimuth of base line ErGun elevation for corrected range Tc Target course angle X Spotterscorrection along X axis YB Spotters correction along Y axis The originof the X coordinate may be taken at the mid point of the base linelength and at right angles to it, and the origin of the Y coordinate maybetaken as the base line.

The derivation of the principal equations may readily be seen byreference to Fig. 10A. In this figure a circle of radius (T) has beenconstructed with the target To and base end stations B2 and B1 in thecircumference of the circlt. The line from B2 to B1 is the baselinelength The lines BZTo and BlTo are the lines of sight from therespective stations to the target. The angle The diameter d--d throughthe center (C) of the circle is made perpendicular to the base line andbisects that line at its mid point (F) because a radius which bisects anarc is perpendicular to the cord of that arc at its middle point. Theline e-e is parallel to the line d-d and, therefore, is perpendicular tothe lines B2Bl, 41-11 and b--b.

Angle 1 equals angle 4 and angle 2 equals angle 3 as alternate-interiorangles. Angle 4):; is the difference between angles 4 and 3, therefore,angle m is also the difference between angles 1 and 2. Since the angleAH2BI is a common factor of both angles z and 4n, the following equationcan be written after substituting and equating:

Also, since an inscribed angle is measured by one-half its interceptedarc, angle 5 equals angle 3. In the right angle triangle B2CF, angle 6equals ninety degrees minus the angle 3. In the isosceles triangleBZTQC, angles 7 and 8 are equal and, therefore, the angle 9 is equal toone hundred and eighty degrees minus twice the angle '7. Angle 7 isequal to one hundred and eighty degrees minus both angles 1 and 6. Angle1 equals 2 minus angle A Angle 4 equals angle 9 plus angle 5 minusninety degrees. The above equities may be Written in equation form asfollows:-

By substituting the first five equations into the last one, andsimplifying, the result is as follows:-

Again referring to Fig. 10A, the distance between the stations B2 and B1is the base line length R5 but since the point (F) is the mid point ofThe hypotenuse of the right angle triangle BzCF is the radius (r) of thecircle and the angle 5 is equal to the angle 3. The sine value of anglea is the distance divided by the distance r, or in equation form:-

2 sin Q53 In the right angle triangle TOCG, the hypotenuse is the radius(r), therefore, the distance (R,,,) can be obtained by employing thecosine function of the angle (4) as in the following equation:-

R 1' cos ..=r sin a and'in the right angle triangle BzCF where the angle5 is equal to angle 3 and the hypotenuse is the radius (T), the cosinefunction of angle (3) is used to obtain (R By the addition of the abovevalue of (R and (R the following equation results:-

The rates of change (Sx and S (Fig. 10) of the coordinates R. and R arecomponent speeds of the target and are preferably measured by variablespeed drives and each rate is multiplied by the projectiles time offlight (t) to the predicted position (Tp) to obtain coordinatesetforward distances Sxt and S t). These coordinate distancesoriginating at the target are added algebraically with others to thematched present position coordinates to obtain the predicted or futureposition coordinates (12, and R of the target.

Provision is preferably also made to set in battery commander coordinatespots (which may be termed X5 and Y5, but are not shown in thedrawings), these distances also being added algebraically to the matchedpresent position coordinates with their origin at the target (To).

The computer is preferably so constructed that there is no physicalconnection between the indicated present position coordinates and thematched present position coordinates. This allows the computer tocontinue to function on the basis of old data when an interruptionoccurs to the observed data. This condition holds for this system andthe two others outlined below.

Since the future position coordinates are to be used to obtain thecontinuous setting of the gun azimuth (Ap) and gun range (R the latterbeing converted into gun elevation (Er) for that range by the computer,it is necessary to convert the algebraic sum of the above X coordinatesinto another sum originating at the gun or directing point (D. P.) Theleft hand base end station (B2) may be arbitrarily selected as theorigin of the directing point coordinates (Xne and YDP) tor, of thevalue of one half the base line length To do this, we add an additionalX fac- The future position coordinates, now originating at the directingpoint, form two sides of a right angle triangle with R. as the base andR as the side at right angles to the base. The bypotenuse of thetriangle is the gun range (Rp) to the future position of the target (Tp)and the angle (ApB) that the hypotenuse makes with the base, when addedto the base line azimuth (A n is the gun azimuth (Ap). In the abovetriangle the known quantities are R, and R with Rp and ApB as theunknowns. By the simultaneous solution of two equations, the continuousflow of range Rp and azimuth ApB is obtained.

12. R, =R,, cos A 14. R,, --R,, sin A 15. A B B pB The azimuth Ap istransmitted electrically to receivers of the follow-the-pointer" type,at the guns. Means is also preferably provided in the computer to set inazimuth deflections for spot and ballistic corrections.

The range Rp is matched by the lift of a cam whose rotational factor isgun elevation (Er). The range (R13) is corrected for spot and ballisticsby means of a per-cent range mechanism that applies range corrections tothe generated range (R before it is matched by the lift of the abovecam. The resulting gun elevation (Er) is transmitted to the guns. Meansis also provided for selection from multiple range-elevation andtimeelevation cams when more than one powder charge or projectile weightis used or where the computer is used for more than one type of gun.

The above method of tracking a target with two azimuth observingstations, one at each end of a measured base line, is commonly known asthe horizontal base system of location.

Two other methods are provided for in our computer, one commonly knownas the vertical base system and the other as airplane observation. Thesesystems are used principally as alternatives in connection with thehorizontal base system when the target cannot be seen simultaneously bytwo observing stations. as when some or all views are cut off by smokescreens, etc., or the target is over the horizon.

When using the vertical base system, one station continuously tracks thetarget in azimuth and sends its data to the computer in the same manneras was outlined above for the horizontal base system. In addition, thisstation measures the range (RB) from it to the target, at regular timeintervals, sending it to the computer. This range is set in and drivenby a variable speed drive whose rate and value can be adjusted as eachrange is received.

The input of azimuth and range from the observing station is used tocontinuously generate and indicate the linear coordinates of the presentposition of the target with the origin of the X coordinate (RXB) at thestation and the Y coordinate (RyB) origin as a base line to a secondstation. This set up is used so that a change can be made to thehorizontal base system when desired without interrupting the flow ofpredicted data to the guns.

3. -A (when using left hand station) A (when using right hand station)7. R B =RB cos.

It now becomes necessary to tie in the matched X coordinate (RXB) withthe horizontal base system coordinate (R, so that the above shift can bemade. To do this it is only necessary to shift the origin of RXB, whichis at its station (B2 or B1) to the mid point of the base line which isthe origin of the horizontal base system R If the left hand station B2is used, a minus value of one half the base line length is added to thematched RXB. If the right hand station B1 is used, a positive value ofone half the base line length is added to the matched RXB- 9. R, R 2(when using B 2 1 10. R =R 2 (when using B handles 32 and 33. Let usassume that there is transmitted to the computer the two target angles 1and 2. Our machine is set up then to solve Equations 1, 2, 4, 5, 6, 11,12, 13, and 15.

Referring first to Figs. 1A and 17 the azimuth angles may be received atthe computer either by telephone at equal time intervals or by asynchronous electrical transmission system. The equal time intervals areusually measured by the regular striking of bells in unison at the baseend stations and at the computer. If done manually, the initial settingof the dial is accomplished from the handle II .which turns shaft I4 andalso shaft 5' through differential 4, shaft 5' turning the dial Ithrough the worm 5. Analternative drive for shaft I4 comprises avariable speed drive including a sliding sleeve I3 .splined to the shaftI4 and having thereon a large gear 313' and a small gear 3I3. In theposition shown in Fig. 17, gear 3I3' meshes with a pinion 2I' on shaft2| for a slow speed drive from the latter, but by moving the changespeed lever I3 upwardly to the first dotted position, gear 3 I3 isbrought into mesh with gear 2| to drive said shaft I4 at a higher speed.In still a third position, gear 3I3 is brought into mesh with gear I2Ion shaft I2 of a power actuated device, hereinafter explained, thusproviding a third drive for shaft I4.

The shaft 2I is shown as driven from a change speed device I6, II whichmay comprise a cylinder IT, a disc I8 continuously rotated from aconstant speed motor I9, and a sliding ball or balls I6 which may bepositioned axially on the cylinder and radially of the disc I8 by meansof a rack bar I6. Said rack bar in turn is positioned by turning therate handle I5 also connected to the rate indicating disc I5.

After the initial angle is set in by rotating the handle II, asexplained, the gear shift lever I 3 .is set either into the positionshown in full lines in Fig. 17 or the first dotted position depending onwhether high or low speed transmission is desired but no motion takesplace because at first the handle I5 is set to position dial I5 at zerowhich positions the change speed controller I6 at the center of disc I8.Before the second reading is received, a second rate dial I5 is set tozero against its index I by means of a knob 2. Said dial and knob arefrictionally mounted on shaft 3I5 driven from the shaft 3' of the handle2 so that the dial I5 normally turns with the shaft 3 but may be setindependently. The second telephoned angle is set into the dial I byturning the handwheel 2 which drives the shaft 3, worm wheel 3 anddifferential 4 to turn shaft 5. Turning the handwheel 2 displaces therate dial I5" relative to the index I by an amount equal to the changein angle between the first and second azimuth angle. This change, whichis really also a rate of change because the time intervals are known andconstant, is immediately set into dial I5 by turning handle I5, thussetting the change speed device I 6, II to drive the dial I at this ratethrough shaft 2| and I 4. Indicator I5 is then set back to zero. Thethird and successive readings are set into the dial I in the same manneras the second reading with the exception of the reading of rate takenfrom the dial I5" which is added to or subtracted from the original rateas the case may be.

Or a power multiplying system may be introduced to rotate the dial I asWell as the dial 6 from the tower B2 in which case hand setting isdispensed with. Said power system may be of any suitable form, such asshown, for instance, in the copending application of Bruno A. Wittkuhns,now Patent No. 1,999,645, for Positional control of heavy objects, datedApril 30, 1935 and assigned to the assignee'of the present invention. Itis represented in Figs. 1A and 17 as comprising a motor II geared toshaft I2 and actuated through an amplifier I24 from the common A. C.supply S and the output of the transmitter-generator I and the polyphasetransformer I. When the power system is operating the sliding gears I3are shifted downwardly by handle I3 to engage the gear 3| 3 thereon withgear I2I on shaft I2 so that the shaft I4 is turned to operate the dialI through the differential 4.

Still a thirdmethod of putting the angle 2 into the machine is bytransmitting the angle by self-synchronous transmission from the basestations and turning the outer dial 6 from a repeater motor and merelymatching the dials I and 6 by operating the handle II. In this case, thehandle I3 is moved to some intermediate position in which all gears areout of mesh and the motor I is merely used as self-synchronous repeatermotor. By these means the angle may be set in the machine by any one ofa plurality of methods.

Similarly the angle 1 is set up upon the dial 24 by mechanism which maybe identical to that for dial I. Since from Equation 1, 3 is thedifference between 7 and 4n, these two angles are subtracted bydifferential 25 connected between shaft 26 driven from I and shaft 21driven from 24, so that the output represented by the turning of theshafts 23 and 23' represents 21. From Equation 2 it should be noted thatthe sum of these two angles is also employed so that at 25' is placed asecond differential which adds these two angles, the result beingtransmitted to the shaft 21 through a differential 28 where the factor 2is introduced from the handwheel 29 which is set on dial 58, handwheel32 introducing KB]? or the X component of the batterys position andhandwheel 33 introducing Ypp. It will be understood that each of thesehandwheels has a connected dial for setting the same.

The angle 3 represented by the rotation of the shaft 23' is introducedinto the angle resolving mechanism 35 through the shaft 36 so as toposition a slot 43 in a gear 42 at the angle 4n. The purpose of thisunit is to solve Equation 4 for 1', that is, the radius of the circle C,i. e.,

R8281 r 2 sin Q53 Said instrument (Figs. 2 and 3) compriscti a pluralityof superimposed members comprising a bottom large gear 38 having aspiral slot therein 39 which is rotated from pinion 64 turned from theshaft 63 and setting handle 6|. Above said spiral slotted gear is asecond gear 42 which has therein said slot or transverse slideway 43 inwhich slides I a block 44. -Said gear is rotated from shaft 23 (43)through shaft 36 and. pinion 40. Said block has a downwardly extendingroller 45 thereon which engages said spiral. Said block also has anupwardly extending roller 46 thereon which engages a transverse trackway41 in a rectilinear slide 48. Said slide is mounted for up and downmovement at right angles to the slot 41 by rollers 49-50 (Figs. 2, 3 and4) which roll along the opposite edges of fixed strip 49'. Said slide 48is also guided at one side by slideway 50. To said slide is secured arack 5|, the teeth of which engage a pinion 52 on a shaft 53. Preferablysaid pinion and shaft is journaled on an arm 54 pivoted at 55 on fixedbar 49 and, is held against the rack teeth by the spring 56. Shaft 53may carry at its outer end an indicator 51 forming a part of afollowthe-pointer indicater 58" and which is arranged to match a pointer258 which is turned from one of the locking handwheels above described,namely, the handwheel which sets in the length of the baseline (RB2B1)then the mechanism will solve the equation r z 2 sin (#3 In operation,after the locking handwheel 30 is set, the operator turns the handwheel6| which rotates gear 38 through shaft 63 and pinion 64 until thepointer51 matches the pointer 25!! set from 30. This function may alsobe performedautomatically by providing a follow-up motor 26l to turnshaft 6| and actuated by follow-up contacts (not shown) on saidindicator 58". Differential 62 and pinion 62 meshing with 42 areprovided to turn gears 38 and 42 together when 42 is turned so that therange setting will not be altered thereby.

The rotation of the shaft 6| is, therefore, a measure of r and may beintroduced into the machine for solving some of the other equations.Firstly, it is introduced through differential 62' and shaft 63' intothe calculating mechanism B which may be similar to calculatingmechanism A except that it solves for the cosine of an angle instead ofsine. We introduce into this mechanism the angle 4 from the shaft 66 sothat Equation 5 is solved. Therefore, the a: coordinate of the positionof the target is located. This value is introduced by matching pointers51' and 258, the former being positioned from the calculating mechanismand the latter from the handwheel 61 or other setting means.

The y coordinate is located by a pair of calculating machines C, thefirst of which has the angle 4 set up therein from shaft 66 and also 1'from shaft 6 l thus giving one half of one part of Equation 6, namely, rsin 4. The second machine has set up therein the angle 4):; from shaft23' and, therefore, solves for the r cos 4n portion of Equation 6. Thetwo results are then added through differential 10 to rotate the pointer"H, the position of which, therefore, represents the 1/ coordinate ofthe target position or R This value may be cranked into the machine bythe handwheel IT2 operating the follow-the-pointer indicator 1|.

Having located the coordinates of the present position of the target, wethen proceed to locate the future position, which, of course, may belocated by the coordinates of the present position plus (or minus) thedistance moved thereby (during the time of flight of the shell) alongthe course of the target, which may also be resolved into a: and 1/components and algebraically added to the components of the presenttarget position. For determining this position, we set up in the machinethe rate of movement of the target in each component direction (8;; andSy) and multiply the same by the line of flight to give Sxt and S t. Thea: rate of movement is set in by the handwheel l2 and appears on dial12'. This handwheel operates to position the change speed element 13 ofchange speed gearing driven from constant speed motor 14 and similar tothat above described.

As above explained, the handwheel 61 is turned to match the pointers 51'and 258' to give the factor It should be remembered, however, that theposition of provided for initial setting. The clutch I3I is used todisconnect the constant speed mechanism at that time.

A similar mechanism is provided for S comprising setting handle 12"change speed gearing 13 which operates shaft "2' through differentialI38.

The Sx rate of movement is introduced into a computing unit E throughthe shaft 15 to turn threaded shaft I8 therein and thereby move a nut'I'I (Figs. 13 and 5). Said nut has a pin I8 thereon engaging a slot I9in a plate 88 secured to a disc 8'I. In said disc is a slideway 82inwhich is slidably mounted a block (not shown) carrying a pin 83projecting in both directions therefrom and similar to the block 44 ofFig. 2;" Above said disc 'is'mounted a cross bar 86 threaded at oppositeends in a pair of threaded shafts 81 and 81'. Said shafts are rotated inaccordance with the time of flight of the shell (t) 'by 'meanshereinafter described or by handwheel I81.

The downwardly projecting portion of the pin engages a transverse slot84' in a slide 84 mounted for up and down movements on a slideway 88 bymeans of rollers in a manner similar to the member 48 of Fig. 2. Slide84 will be given a movement proportional to the product of Sx and t, orin other words, in proportion to Sxf, or the a: component of thedistance of Tp from To. Similarly the 1 component is calculated from Syand t by a calculator E which may be identical to E, Sy being introducedthrough shaft I12" to threaded shaft I6 and t through 81. This movementof the slide 84 (of the machine E) is transmitted by means of the rackbar 89 to a pinion 98' (Fig. 1B) where the value Sxt is added to otherportions of Equation 11 through differential 88. Thus the hand setting32 introduces XDP or the X component of the guns position, which issubtracted from R3 13, coming in through shaft 9I and gears 9I' and 9|"to differential 92 and said combined factor is in turn added to Rxothrough differential 93, the spotters correction XS being introducedfrom handwheel I28 through the differential I 2I so that the rotation ofshaft 94 represents Rxp or the a: coordinate of the future position ofthe target from DP.

Similarly, Equation 13 is solved-for RYP by exactly similar mechanism asshown in Figs. 13 and 1C. Thus Ynp is put in through the handwheel 33,the spotters correction through handwheel I25 and the expressions R andY1)? are added and substracted through the differentials 95 and 96 andSyt introduced through differential 91 from rack bar 89' the finalresult. namely, RYP, positioning the pointer 98 on indicator 99.Similarily, RxP positions the indicator 98' on indicator 99'.

The factors that are wanted, however, are the range and bearing angle ofthe future position Tp of the target from the guns DP which is shown inFig. 10 as angle AP or merely APB and distance Rp. These are obtainedsimultaneously from a pair of computing mechanisms D, in both of whichare introduced APB and Rp. Said mechanisms may be similar to thosepreviously described. Two setting handles are provided I88 and I8I, fromthe one of which is derived'the angle APB and from the other the rangeRp, the

pointers I82 with 98 and I82 with 98'. Or the matching may be obtainedautomatically through follow-up motors I88 and I8I controlled bycontacts on instruments 99 and 99 respectively (see Fig. 18 describedhereinafter). This cannot be accomplished except by turning thehandwheels together as each handwheel effects both pointers, since inthe two Equations 12 and 14 two unknowns are being solved. Handwheel I88is shown as turning the shaft I83 through worm and wormwheel I84 andmoves the radially slotted member 42 of the calculating mechanism I85.In this instance the spiral disc 38 is set from shaft II8 which, as willbe observed, is turned from handwheel IIII through worm I I I. Themovement of the slide 48", therefore, wnr'b proportional to R1) sin ApB.In the other calculator I85, the angle A1713 is set in by means of shaftI I2 geared to shaft I83 and Rp is set in from shaft I I8 throughdifferential I I3 and shaft I I4, thus positioning the slide 48 to matchpointers .I82' and 98'. Since both pairs of pointers on indicators 99and 99 are simultaneously matched, the two equations are simultaneouslysolved for the two unknowns Rp and angle AP, the former appearing as therotation of the shaft I I8 on the dial I I5 and the latter appearing asthe rotation of the shaft I83 on the dial H6. The angle ApB derived fromthe calculating units I85 and I85 driving shaft I83 passes through adifferential I83 before driving shaft I83. In order to obtain the fullangle Ap with reference to the orienting point 0 (see Fig. 10) the angleA3 8 is added to Ap by the differential I83 being set into saiddifferential by shafts 298 and handwheel 29 (Fig. 1A).

As shown in Figs. 6 and '7, the shafts of the handwheels I88 and IM runstraight through the machine, duplicate handwheels being on each side.On the other hand, the R indicator 99 is placed only on one side of themachine and the R, indicator 99 only on the other side of the machinewith one operator matching the X coordinates and the other the Ycoordinates, both operations occurring simultaneously as aboveexplained, but which handwheel (I88 or I8I) each operator employsdepends upon the quadrant location of the target, because the operatorsin turning the handles are really converting the polar coordinates ofrange Rp and azimuthal bearings ApB into rectilinear or X and Ycoordinates. A consideration of the diagram shown in Fig. 19 will showthat there are times when the observer of the R dial 99 should beoperating the handwheel I88, that is the azimuth handwheel, and othertimes when he should be operating the range handwheel IIII andconversely with the observer of the R indicator 99'.

Thus, if the target is located at point T1 in Fig. 19, it will readilybe seen that a change in the angle APB is more effective in obtainingthe coordinate Ryp than a change in the range Rp, while a change in therange Rp is more effective in obtaining the coordinate Rxp than a changein the angle APB. Similarly, if the target lies at the point T2 it mayreadily be seen that a change in the angle is more effective inobtaining the X coordinate and a change in range is more effective inobtaining the Y coordinate. In other words, that somewhere between thepoints T1 and T2 the Ryp operator (observing indicator 99) In general,it may be stated that for target positions lying between 45 lines L andL3, the observer of the Y dial 99 should use handwheel I00 while theother observer uses the handwheel IOI, while in the quadrant between 45lines L and L1 the reverse is true. Between quadrants L1 and L2 the sameconditions prevail as between L and L3 except that the signs arereversed. or, in other words, the handwheels have to be rotated in theopposite direction, while between L2 and L; the conditions are similarto the conditions between L and L1 except that the signs are reversed.

With manual operation the operators can be depended upon to shifthandwheels at the proper time by their experience with the machine, butin case power follow-up system is employed, it is necessary to providean automatic means for making this change-over. Such a means is shown inFig. 18. According to this system, each of the indicators 99 and 99' areprovided with trolleys 253 and 253' secured to rotate with the pointersI02 and I02 and the follow-up rings 252 and 252' secured to rotate withthe followup pointers 98 and 98', respectively. Said contacts controlthe operation of the reversible power motors I00 and I0 I through aseries of relays R. For effecting the change-over control of the motors,we have shown a selector switch 26| which is laid out so as to transfercontrol near the 45 lines referred to in Fig. 19, a switch arm 262 beingmounted on the shaft I04 of the handwheel I00. Said switch is providedwith four contact sectors I1, I2. l3 and I4. Each sector is preferablyslightly greater than 90 so that there is an overlap of a few degreesadjoining each pair of sectors as indicated by the shaded sectors inFig. 19. By means of interlocking relays R1,. the operation of which iswell known in the electric motor control art and need not be describedin detail, the control of the motors may be transferred and theirdirection reversed in accordance with the position of the switch arm 262on the selector switches but within the overlapping regions the motorwill remain in control of the contact sector first assuming controluntil the switch 262 leaves the same and rests only on the other sector.This is for the purpose of preventing rapid transfer of control of themotors in case the target is traveling near one of the 45 lines L.

Both shafts I03 and H0 are preferably connected to a data computer andtransmitter of the form shown in our copending application, now PatentNo. 1,999,368, datecLApril 30, 1935, where Rp or range is corrected byballistics and spots (as percent range) and converted into Er(gun'elevation for corrected range). Er is returned to the machinethrough the shaft III and appears on dial 1'.

The elements of this machine are shown in Fig. 1D. The range coming inthrough shaft H0 is transmitted through shaft 220, differential 22 I,shaft 222, gearing 222' and differential 223 to a follow-the-pointer orzero reader indicator 224, The duty of the operator of the handwheel 225on shaft 225' (or the function of a follow-up turning the same) is tokeep the indicator 224 reading zero. Turning of said handwheel operatesthe elevation shaft III and also the elevation transmitter 226. Itsconnection to the zero reader is through the differential 223 beingturned in the opposite direction by the shaft 240 as follows. Turning ofthe handwheel 225 turns through gearing 221 a shaft 228, on which ismounted a series of range elevation cams 229. A plurality of cams areprovided for different types of guns and powder charges, only one cambeing used at a time. Cooperating with the same is a follower 230 whichmay be positioned over any one of the cams by turning the handwheel 23Iwhich rotates the single toothed pinion 232 to move the rack 233 whichcarries the pin 230. Preferably the pin is lifted at the time it isshifted by the eccentric cam 234 which lifts block 235 and with it thepin whenever the toothed pinion 232 is rotated through a revolution.There may also be provided a high and low angle fire indicator 236operated from a shaft 225' of handwheel 225 and from rack bar 233, asexplained in the aforesaid application, and the name or number of suchcam or zone as is being employed may be transmitted to the gun throughzone" transmitter 231 also driven from the rack bar 233.

The lift of the pin 230 is a measure of the range for any givenelevation and this lift is shown as transmitted to the indicator 224through the slide 238 resting thereon which has rack teeth out thereonto turn the pinion 239 and thereby turn the shaft 240 and rotate thedifferential 223 to bring the indicator 224 back to zero. It is obviousthat a power follow-up system may be employed for shaft 225 actuatedfrom contacts on the indicator 224, if desired.

Range corrections may also be introduced by one or more handwheels 240and MI. The handwheel 240 may be used to introduce spotting correctionsas a percentage correction in range, while handwheel 24I may be used tointroduce a ballistic correction also as a percentage range correction.These two corrections are combined through differential 242 to turn athreaded shaft 243 which moves laterally a lift pin 244. Said pin mayhave rack teeth thereon to turn a long cylindrical pinion 245 when thepin is lifted or lowered. Said pin may rest on a lever 246 pivoted at241, which lever is positioned about its pivot by the lift of a pin 248on an arbitrary percent range cam 249 turned from the shaft H0. The liftof pin 244 is, therefore, proportional to the percentage of the rangeselected by the correction handwheels and is transmitted as aproportional correction to shaft 222 through the differential 22I.

The final target bearings Ap are shown as indicated on dial 250 and aretransmitted through the azimuth transmitter 25I to the guns. Thespotters correction may be also introduced through a handwheel 252through differential 253. Our computer, therefore, transmits to the gunsall necessary data for firing, namely, the elevation, target bearings inazimuth and the zone employed.

The elevation as determined as above described is introduced into ourcomputer by shaft II'I. Said shaft positions a series of time of flightcams II8 which operate lift pins I I9. Several cams are provided so thatthe machine may be used with guns of different characteristics. Fivesuch cams H8, 8', etc. are shown in Fig. 14, but it will be understoodthat any desired number may be em ployed. A lift pin H9 is provided foreach cam, each pin being mounted in a slide I40 which is slidablymounted in a framework I4I (Figs. 9, 14 and 16). At one side of theslides there is mounted a movable carriage I42 which may be moved up anddown by the rotation of a threaded shaft' I43. Said shaft is rotatedfrom a follow-up motor I44 (see Fig. 1B) which rotates shaft 81connected to screw shaft I43. Said motor is controlled by a contact armI45 pivoted on said carriage and adapted to make contacts I46 or I41 tooperate said motor in opposite directions to raise and lower saidcarriage. Preferably contact arm I45 is made in the form of an angle barpivoted at I48 to a second angle bar I49 which in turn is pivoted to thesupport I42 at I50. Both bars have their lower ends connected by springsI5I and I5 I to the support so that the lower contact I41 is closed whenthe beveled knife edge I52 of. arm I45 is pushed up, rotating arm I45counter-clockwise (Fig. 16), the member I49 being held against the fixedstop I55 by the spring I5I. Said edge is adapted to be engaged by ashoulder I53 on slide I40 so that as said slide moves down it tends tomove away from said edge and spring I5I' rotates the bar I45 clockwiseto make the upper contact I46. The result is that carriage I42 ismaintained in the same position with respect to the engaging end of thecam follower II9, which position is proportional to the time of flightof the shell, the latter being transmitted through the shaft 81 to thecalculating mechanisms E and F for computing It should be noted thateven though the follow-up mechanism fails, the contacts will not bedamaged because if the carriage I42 is rising, for instance, and themotor fails to respond, the arm I45 will be bodily pushed to the left inFig. 9 or 16 about pivot I50 as a center before any great pressure isexerted on the contact I41. It will be understood that a set of contactsis provided for each'cam follower, but that only a selected one is usedat a time to control the motor I44. This may be effected by leading oneof the common wires through a push pin 20I which is plugged into one ofa-series of holes 202 corresponding to the cam desired to be used. Itwill be understood that the cam selected corresponds to the rangeelevation cam 229 used in Fig. 1D.

As above explained, our machine determines both the X and Y componentsof the course of the target, 1. e. Sx and S From these values agraphical representation of the targets course may be shown on themachine. Thus in Figs. 11

to 13 and in the lower left portion of Fig. 1C is shown such anindicator in which a horizontal cross hair I10 is positioned inaccordance with S from an extension I15 of shaft 16' of machine E orfrom handwheel I 15, and a vertical cross hair "I is positionedlaterally in accordance with 8x either automatically or from handwheelI13 and the shaft or shafts I16 driven from shaft 16 of machine E. Thecross hairs are stretched over nuts 218 threaded on said shafts andguided on trackways 218 and are held under tension by springs 219. Undersaid cross hairs are two rotatable dials, the outer one (I18) of. whichis in the form of a ring having an index marked 0 thereon representingthe angle and marked target course". Said ring is rotated from shaft I19set from the handwheel 29 through shafts I8I and I19. Inner dial I84represents the enemy ship or target I84 and has a fore and aft graduatedcenter line I thereon. The circumference thereof is also graduated indegrees on which index 0 is read. This dial is turned from handwheel I86so as to maintain the intersection of the cross hairs I10 and Ill oversaid center line I85. The angle, therefore, read on index 0, is the truetargets course To (Fig. 10) while the distance along the line I 85 (Fig.11) as shown by the graduations thereon, shows the actual speed S of thetarget, the component speed being shown by the linear graduations I89and I on which the cross hairs I10 and Ill may be read.

Preferably we also design the machine so that the target may be locatedwhen one of the base stations cannot be used for any reason, such as,where the target is visible from only one station. According to thissystem the station in use (B2 or B1) continuously tracks the target inazimuth and sends its data to the computer in the same manner asoutlined above. In addition, this station also measures range RB from itto the target at regular time intervals sending this information also tothe computer. This range is normally set in through a handwheel I32(Fig. 1A) which positions the range dial I33 and turns the shaft I34.Preferably, as in the angle receiving mechanism, we also employ avariable speed device I6" positioned by handwheel I34' so that theproper rate of change is set up in accordance with the received data.This input of azimuth angle and range from the observing station is usedto continuously generate and indicate the linear coordinates of thepresent position of the target with the origin of the X coordinate RxBlat the station and the Y coordinate R origin as the baseline to theother station.

By reference to Fig. 10, it will readily be seen (using station B2, forinstance) that Equation (7) is solved by computing machine G into whichrange is introduced from shaft I34 to shaft I35 and is introduced fromshaft I36 driven from shaft I31. Said shaft is adapted to be driven fromeither station 1 or (p2. In the former case, the clutch handle I38 ismoved to the right and in the latter case to the left. The angle beingset in through the handwheel 29, as above explained, is subtractedthrough the differential I53 so that the movement of shafts I31 and I 36represents the angle Said mechanism G may be similar in all respects tomechanism B above described, the pointer or dial I54 indicating RXB.Similarly, RyB is computed from the computing mechanism H (Fig. 1B) intowhich is set the range RB from the shaft I34 through shaft I35 and theangle through shaft I31 and I31. The mechanism H solves Equation 8 sothat the indicator I56 indicates the Y coordinate of target positionwhich is also R because the baseline B2Bl is taken as the origin of theY coordinate in both systems.

The X coordinate, however, is taken from station B2 (or B1) instead offrom the diameter dd of the circle, as in the previously describedsystem so that in order to utilize the mechanisms of the other system,it is necessary to transfer the X coordinate to the same origin. To dothis it is only necessary to shift the origin of RxB to the mid point ofthe baseline. If the

